Hydrogen ameliorates oxidative stress via PI3K-Akt signaling pathway in UVB-induced HaCaT cells.

Chronic ultraviolet (UV) exposure-induced oxidative stress is associated with the pathogenesis of skin damage. However, the nuclear factor erythroid‑2‑related factor 2 (Nrf2) pathway is a critical factor in protecting cells against UVB‑induced injury through inhibiting oxidative stress. Furthermore, Nrf2 activation requires the involvement of the phosphoinositide-3 kinase (PI3K)/protein kinase B (AKT) pathway, which has a major role in survival of various cell types. Molecular hydrogen exerts protective effects on UV‑induced injury, but the underlying mechanisms have remained elusive. The present study assessed the protective effects of hydrogen against oxidative stress‑induced injury caused by UVB irradiation and investigated the molecular mechanisms. In vitro, UVB‑induced HaCaT cells were collected for the detection of reactive oxygen species, 8‑iso‑prostaglandin F2α, malondialdehyde via fluorescence spectrometry and ELISA; cell activity and cytotoxicity by MTT and lactate dehydrogenase assays, respectively. Additionally, the expression level of PI3K, Akt, Nrf2 and heme oxygenase‑1 (HO‑1) were investigated using western blot, etc. All of the results indicated that hydrogen decreased the levels of reactive oxygen species, 8‑iso‑prostaglandin F2α and malondialdehyde, and promoted the UVB exposure‑induced expression of PI3K, Akt, Nrf2 and heme oxygenase‑1 in HaCaT cells. Of note, PI3K inhibition partially reversed the effects of hydrogen on UVB‑induced HaCaT cells. Therefore, hydrogen effectively protects cells from UVB radiation‑induced oxidative stress by inhibiting Nrf2/HO‑1 activation through the PI3K/Akt signaling pathway.